Can someone explain whats happening to $e in this

Hi, Can someone explain in english what this is doing to email addresses? Is it validating the users input format?I've got 2 Buy Now buttons that take people to Paypal but then Paypal says error wrong email address.

Yet above this code $ppe is set as my correct paypal email address. This is from my config.php.

That's the link to paypal so on the sales page he just writes $button_url$paypal2 should be the users email address$ipn_link don't know what this is (notify url) but he's turned it off (commented it out) previously

I don't see any reference to my paypal account could this be why paypal says error wrong email address to the buyer?

I'm not too familiar with this part of PayPal but I believe the business= is your email address, not the customer's.

Separately, it looks like you're putting the notify_url for IPN in the URL you're redirecting too? That should be specified in your account instead. Exposing that location to the user is a risk to your listening code, and though it should not be a problem (because it verifies the request with PayPal) there's always the chance of a malicious user discovering an exploit in the code. I don't know how it was "turned off" so this may not be a problem.